RESUMO
A patogenia da leishmaniose tegumentar americana (LTA) na Amazônia foi revisada à luz dos mais recentes aspectos associados ao espectro clínico, histopatológico e imunopatológico da doença causada por Leishmania (V.) braziliensis e Leishmania (L.) amazonensis. Esta revisão mostrou a existência de uma dicotomia entre as duas espécies de Leishmania e a resposta imune celular; enquanto a L. (V.) braziliensis mostra forte tendência em dirigir a infecção, a partir da forma central do espectro clínico-imunológico, a leishmaniose cutânea localizada (LCL), para o pólo imunológico hiperreativo, representado pela leishmaniose cutâneo-mucosa (LCM), com exacerbação da hipersensibilidade e perfil da resposta CD4 tipo-Thl, a L. (L.) amazonensis mostra o oposto, dirige a infecção para o pólo imunológico hiporreativo, representado pela leishmaniose cutânea anérgica difusa (LCAD), com forte inibição da hipersensibilidade e perfil da resposta CD4 tipo- Th2. Entre a forma central LCL e as formas polares LCM e LCAD a infecção passa por uma fase intermediária, a leishmaniose cutânea disseminada borderline (LCDB), com inibição parcial da hipersensibilidade e peifil da resposta CD4 Thl + Th2. Estes são, provavelmente, os principais mecanismos imunológicos que modulam a patogenia da LTA causada por L. (V.) braziliensis e L. (L.) amazonensis.
The pathogenesis of American tegumentary leishmaniasis (ATL) was reviewed ifl the light of more recent features of clinical, histopathological and immunopathological spectrum of disease caused by Leishmania (V.) braziliensis and Leishmania (L.) amazonensis. This review has shown a dichotomy in the interaction between these two species of Leishmania with the human .cellular immune response; while L. (V.) braziliensis shows a clear tendency to direct infection, from the localized cutaneous leishmaniasis (LCL) in the center of the clinical-immunological spectrum of disease, to the hyperactive immunologic pole represented by mucocutaneous leishmaniasis (MCL), which shows exacerbated hypersensitivity reaction and CD4 Thl-type immune response, L. (L.) amazonensis shows the opposite,. directing infection to the hypoactive immunologic pole consisted by anergic diffuse cutaneous leishmaniasis (ADCL), associated with a marked inhibition of hypersensitivity reaction and CD4 Th2type immune response. Between the central LCL and thetwo polar MCL and ADCL forms the infection may present an intermediary phase, borderline disseminated cutaneous leishmaniasis (BDCL), which shows partial inhibition of hypersensitivity reaction and a mixed CD4 Thl plus Th2 immune response. These are probably the main immunological mechanisms regarding the immune response dichotomy that modulates the pathogenesis of ATL caused by these Leishmania parasites.
Assuntos
Ecossistema Amazônico , Leishmania braziliensis/imunologia , Leishmania/imunologia , Leishmaniose Cutânea/patologia , BrasilRESUMO
Experimental animal models have been used for the study of the physiopathogenesis of leishmaniasis, on some occasions with success, while in other situations such as bone alterations that accompany tegumentary leishmaniasis, especially in diffuse cutaneous form (DCL), the mechanisms are still unknown. In the present study, we determined these alterations in an animal model susceptible to Leishmania (L) amazonensis. Amastigotes of L. (L) amazonensis isolated from patients with diffuse cutaneous leishmaniasis (DCL) were inoculated into the hind paws of eight BALB/c mice, macroscopic and histopathological aspects were analyzed. After 90 and 120 days of evolution, histopathological analysis demonstrated a mononuclear cell infiltrate rich in plasma cells and intense parasitism of intra- and extra-medullary macrophages, with areas of bone necrosis and discrete involvement of cartilaginous tissue. The results show that the inflammatory process developed during L. (L) amazonensis infection might cause bone tissue destruction and secondarily affect the joints.